Temperature-controlling flatiron stand



Sept. 30, 1941. sAHLl 2,257,131

TEMPERATURE-CONTROLLING FLA'IIRON STAND Filed April 5, 1939 T1 II .1

INVENTOR losse 7* 54 H4 B {M fl, ATTORNEY Patented Sept. 30, 1941 UNITEDSTATES PATENT OFFICE Robert Sahli, Basel, Switzerland Application April5, 1939, Serial No. 266,110 In Switzerland February 24, 1939 2 Claims.

This invention relates to a flatiron stand with automatic disconnectionof the heating current when the working temperature of the fiatiron isexceeded and automatic reconnection with the aid of a bimetallic strip.

Flatiron stands of this type are known, in particular also those inwhich the massive metal plate forming the shelf surface of the grid isconnected with a bimetallic strip, the deflection of which upon heatingcontrols a mercury switch positively.

The previously known stands of the said type exhibit many disadvantages,however, which become of importance especially in the frequentlyoccurring case of ironing heavy laundry, for example starched laundry,or in the case where evaporation takes place on ironing damp clothesetc., whereupon large quantities of heat are rapidly withdrawn from theflatiron. In such cases the flatiron, after it has been switched 01f,must very rapidly be switched on again since otherwise it would cooldown too far. The most favourable time for reconnection amountsaccording to experience to about 30-50 secs. Electrical stands whichrequire a connection time of 2-3 mins. or more are therefore notutilisable industrially. Such short connection times however cannot beobtained with the previously known stands with mercury switches becauseof the manner of their construction.

It is an object of the invention to provide a fiatiron stand withautomatic disconnection of the heating current when the Workingtemperature of the flatiron is exceeded and automatic reconnection withthe aid of a bimetallic strip,

which is characterised in that the massive plate forming the stand has aslot which is covered with a thin sheet metal strip of low heatcapacity, to which one end of a bimetallic strip is secured, whilst thefree end thereof acts upon a lever system which is connected with amercury switch, the construction and arrangement of the lever systembeing so chosen that the deflection of the bimetallic strip is magnifiedand the mercury switch is only operated after a definite period of timeafter the beginning of the deflection of the end of the bimetallicstrip, whilst means are further provided for returning the lever systemtogether with the mercury switch into the position of rest.

An embodiment of the invention is illustrated by way of example in thedrawing, in which- Fig. 1 shows a partially sectioned side elevation ofa flatiron stand according to the invention, and

Fig. 2 shows a partially sectioned end elevation.

the thin and narrow sheet metal strip I pro- .vided with holes la andcovering the slot 2a of the carrier plate 2, whilst the free end lc ofthe bimetallic strip is bent away from the sheet metal strip l. Thebearing member 3 for the screwthreaded spindle 4 is arranged upon thewall 21) of the stand housing. The block 6 which carries the levers 7,la, the rod 9, the lever 8, the pivoted mercury switch H and the returnmeans I0 is secured to the screw-nut 5. The double-armed lever 1, 1a issecured to the shaft lb. The singlearmed lever 8 is secured to the pivotshaft 82). The lever arm la is connected articulatedly through the rod 9with the lever 8.

The spring l0 serves for returning the lever system and the pivotedmercury switch to the starting position. The screw-nut 5 together withthe block 6 can be raised and lowered along the spindle 4 by means ofthe bevel gears l2 and I3, the shaft l4 and the crank 15 arrangedoutside the housing to move over a scale (not shown), graduatedaccording to the degree of heat, whereby it is possible to increase orreduce the distance between the free end Ic of the bimetallic strip andthe lever arm I and hence to increase or reduce the lost motion.

The manner of operation of the apparatus is as follows:

The flat iron traversed by current is placed upon the sheet metal stripI whereby the latter is heated and transmits heat to the bimetallicstrip la, as a consequence of which the free end 10 of the bimetallicstrip curves down towards the lever arm 7. Because of the distancepresent between the end lc of the bimetallic strip and the lever arm 7,it will take a certain time, depending upon this distance, before theend is will press upon the lever arm 1 (lost motion). By operation ofthe crank i5 the block 6 can be raised or lowered, so that when the fiatiron reaches a predetermined temperature the end is of the bimetallicstrip begins to press upon the lever arm I, whereupon the mercury switchis operated after a certain time and the heating current is switchedoff. When the cooling of the fiat iron which now begins has proceeded sofar that the pressure of the end lc of the bimetallic strip upon thelever l ceases, the current is then automatically switched on again andthe iron begins to be heated again. This operation is repeatedregularly.

Of course the levers of the lever system may be arranged with respect toone another in another manner than that described above. Thus, for ex-I'he bimetallic strip lb is riveted at one end to 55, ample, the lostmotion may be arranged to take place at other parts of the lever systeminstead of between the end of the bimetallic strip and the first leverof the lever system, or instead of connecting the two levers of thelever system articulatedly with one another, an articulated connectionmay be arranged at another part, for example between the end of thebimetallic strip and the first lever.

The block 3 may also of course be constructed in another manner, andinstead of being mounted on the side wall of the stand housing may bemounted upon another part of the housing, for example on the floor orthe cover thereof.

What I claim is:

l. The combination with a stand for an electric iron, of means mountedtherewith through which current is supplied to the iron, and heatcontrolled means mounted therewith for cutting on? current to the ironupon a rise of tempera:

ture of the heat controlled means when the iran prising in combination aperforated metal strip of low heat capacity and directly contacting theiron when on the stand, a bimetallic thermostat element directlyconnected at one end with said metal strip, a lever system adapted to beengaged and actuated by the other end of said thermostat element upondeflection thereof under the influence of heat and to augment themovements of said other end, an electric switch meansconnected with saidlever system and adapted to cut off the electric current when said leversystem is actuated by the deflected element, and return means connectedwith said switch means for re turning said switch into current switchingon position when said lever system is not actuated, said thermostatelement, said lever system, and said switch means being so constructedas to move in the same plane when actuated by the heat absorbed by saidmetal strip.

2. The combination with a stand for an electric iron, of means mountedtherewith through which current is supplied to the iron, and heatcontrolled means mounted therewith for cutting off current to the ironupon a rise of temperature of the heat controlled means when the iron ison the stand, and for immediately switching on the current to the ironupon a fall of temperature of the heat controlled-means when the iron isoff the stand, said heat controlled means comprising, in combination, ametal strip of low heat capacity and directly contacting the iron whenon the stand, a bimetallic thermostat element directly connected at oneend with said metal strip, a lever system adapted to be engaged andactuated by the other end of said thermostat element upon deflectionthereof under the influence of heat and to augment the movements of saidother end, an electric switch means connected with said lever system andadapted to cut oil the electric current when said lever system isactuated by the deflected element, return means connected with saidswitch means for returning said switch into curent switching on positionwhen said lever system is not actuated said thermostat elernent, saidlever system, andsaid switch means being soconstructed as to move inthesame plane when actuated by theheat absorbed by said metal strip, acommon mounting means for said lever system and said switch, and anadjustable support and pos ition changing means for said mounting meansfor simultaneously, adjustably changing the position of said leversystem and said switchwith respect to said thermostat 'element, saidsupport and position changing means comprising a threaded spindle, bevelgears connected therewith, and a revolvable adjusting shaft connectedwith said bevelgears and extending outside of said stand, whereby uponmanipulation of said shaft fine adjustment of the position of saidmounting means is efie cted.

ROBERT SA'HLI.

